Thread-cutting mechanism for sewing-machines.



F. ZALESKI.

THREAD CUTTING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED NOV. 2. I914.

1,153,148, PatentedSept. 7, 1915. I 2 SHEETS-SHEET l.

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F. ZALESKIQ THREAD CUTTING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED NOV. 2. 1914.

1,153,148. PatentedSept. 7, 1915.

-2 SHEETS-SHEET 2.

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Witnesses. inventor.

/M% E'ranK ZulesKi, 'M- M I y Am 's;

FRANK ZALESKI, OF SOMEBVILLE,

MASSACHUSETTS, ASSIGNOR TO THE LEECE BUTTON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE,

THREAD-CUTTING MECHANISM FOR SEWING-.MACHINES.

Specification of Letters Patent.

Patented Sept. 7, 1915.

Application filed November 2, 1914. Serial No. 869,726.

To all whom it may concern Be it known that I, FRANK ZALESKI, a

. subject of the Emperor of Germany, residing at Somerville, county of Middlesex, State of Massachusetts, have invented an Improvement in Thread-Cutting Mechanism for Sewing-Machines, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention has for its object to provide a novel thread-cutting attachment for sewing machines which is constructed to operate automatically to cut the thread at the end of a predetermined stitching operation.

I have herein shown my invention as it would be applied to a buttonhole sewing machine of the Reece type. Examples of buttonhole sewing machines of this type are shown in the following United States patents: No. 494,280, March 28, 1893; N o. 498,216, May 23, 1893; No. 655,637, August 7 1900.

7 I desire to state, however, that the invention is not necessarily confined in its use to a buttonhole sewing machine but might be with suitable modifications applied to other tvnes of sewing machines.

A buttonhole sewing machine of the Reece type is provided with a bed carrying work-clamping mechanism usually com prising clamp plates and a clamp member movable toward and from the plates to clamp the work to the plates, and a so-called stitch-frame which carries upper and under thread mechanism, said stitch-frame and bed being movable relative to each other during the operation of sewing the buttonhole.

Inthe illustrated embodiment of my invention I have mounted a novel thread-cutting device on the stitch frame and have provided means actuated by the devices controlling the upper thread mechanism to actuate the cutter to cut the upper thread when the stitching on the buttonhole has been completed, the cutter operating between the clamp and the clamp-plate. V

In order to give an understanding of my invention I have illustrated in the drawings a selected embodiment thereof showing the invention as applied to a buttonhole sewing machine of the Reece type, and in the drawings Figure l is a side view of a portion of the main frame or bed and the stitch frame showing my improved thread cutter; Fig. 2 is a front view of the same parts; Fig. 3 is a horizontal sectional view; Fig. 4 is a detail of the arm by which the cutter is actuated.

In the drawings 1 represents the main frame or bed of a buttonhole sewing machine of the Reece type which carries clamp plates 2 and a clamp 3 which is movable toward and from the clamp plates to clamp the work against the plates. I have shown the front portion of the stitch frame at 4 and this stitch frame carries both upper and under thread mechanism, the under thread mechanism being located beneath the bed frame and the upper thread mechanism being in the form of a needle 5 carried by a needle bar 6. In buttonhole sewing machines of this type means are provided for rotating the upper and under thread mechanism as the stitches are formed around the ends of the buttonhole, the means for rotating the upper thread mechanism being in the form of a pinion 7 through whichv the needle bar reciprocates and asector 8 for rotating the pinion, the sector being operated by suitable mechanism to give the pinion its proper rotative movement to effect the turning of the upper stitch mechanism around the ends of the buttonhole.

The construction above described is that found in the well'known Reece buttonhole sewing machine and needs no further description as its operation will be apparent by reference to the aforesaid patents.

In the construction illustrated I have provided a thread cutter 9 which is adapted to act on the upper or needle thread 10 to cut the latter at the time that the stitching operation on the buttonhole has been completed. This thread cutter 9 is shown as'mounted on a rock-shaft 11 journaled in suitable bearings 12 secured to the stitch frame 1. and it is arranged to operate between the work clamp 3 and the clamp plates 2.

While the cutting movement of the thread cutter might be secured from any suitable movable part of the machine, I find it convenient to operate it from the pinion 7, for by so doing the thread-cutting movement of the cutter can be given at the proper point in the cycle of operations.

type during the stitching of a buttonhole the stitch frame and clamp frame have first a .relative movement in the direction of the length of the machine to bring the work into proper position to be acted on by the stitchforming mechanism, and then the stitching operation begins and the stitch frame and bed have a relative feeding movement to cause the stitches to be formed down oneside of the buttonhole and then back on the other side of the buttonhole, the stitch-forming mechanism being rack 8 and pinions as the stitching is car.-

ried around each end of the buttonhole.

When the buttonhole is completed the clamp 3 is automatically released and'moves upwardly from the work into the position shown in'Fig. 1, and then thestitch frame and clamp frame have a further relative movement to bring the parts into their imtial position. During this further relative movement the pinion 7 is turned by its sector to bring the upper stitch-forming mechanism back again to its initial position.

make use of this latter movement of the pinion 7 for giving the cutter its thread-cutting movement, and this is accomplished herein by providing the pinion with a depending finger 13 and providing an arm 14 on the rockshaft 11 which is engaged by the finger during the final turning movement of the pinion 7 thereby to cause the thread cutter to have its threadcutting movement. The arm 14 is shown as loosely mounted on the rock-shaft 11, it being rigid with a sleeve 15 mounted to turned by means of the whichv they assume when the machine is at rest and before the stitching operation is commenced. Y

During the stitching of the buttonhole the pinion 7 is turned first in the direction of the arrow a, Fig. 3, for a little over half a revolution, while the stitch frame and clamp frame are having their initial movement to bring the stitch-forming mechanism into the proper posltlon to act on the work clamped by the clamps 2 and 3, and then after the stitching on the buttonhole begins and one- -side of the buttonhole has been stitched, the

pinion is turned back again in the direction of the arrow b to stitch first around one end completed then the stitch frame and'the bed turn on the rock-shaft. This sleeve is provided with a projection 16 which plays in a notch 17 formed in a collar 18 fast on the rock-shaft and a spring 19 is employed which is connected at one end to the sleeve and at the other end to the collar, which spring normally tends to hold the arm 14 in a position determined by the engagement of the projection 16 with the shoulder 2 of the notch. The rock-shaft 11 is also acted upon by a suitable spring 21, one end of which is secured to the rock-shaft and the other end of which is fastened to the stitch frame or the bearing for the rock-shaft and which" spring normally tends to hold the cutting knife in its inoperative position shown in Figs. 1 and 2.

22 is a stop rigid with the rock-shaft and adapted to limit its movement in the direction in which it isurged by the spring 21.

The object of having the arm 14 loosely mounted on the rock-shaft and capable of a limited rotary movement thereabout is to permit the finger 13 to wipe by the arm as the pinion 7 turns during the stitching of the buttonhole.

Fig. 3 shows the partsin the position frame have a relative movement to bring the parts into the relative position shown in Fig. 1, and during this movement the clamp 3 is released and automatically assumes'its open position shown in Fig. 1, all as will be obvious to those familiar with this type of sewing machine. During this final relative movement of the stitch frame and bed frame the pinion 7 has a turning movement in the 'by giving the cutting knife 9 a swinging movement of sufiicient extent to meet and cut the needle thread. This cutting knife is so positioned that it will pass between the clamps 3 and clamp plates 2 closely adjacent to the work, and as aresult the needle thread is automatically severed close to the work. When the cutter is in its inoperative position shown in full lines Fig. 3 it is at one side of the stitch-forming mechanism and is entirely out of the way.

The projection 16 is normally in 10&

The shape of the arm 14 is such that the movement which will be given to it by the finger 13 is a comparatively quick movement, thus giving the 'cutter a correspondingly quick movement which will readily sever the .needle thread. In some sewing machines of this type the clamp 3 is Pro-.

.vided with a finger or bar 25 which engages the needle thread 10 when the stitch frame mechanism to give and bed frame have their final relative movement, said bar operating to draw the needle thread out into theposition shown inFig. 1. This holds the needle thread under tension so that it will be more readily severed the cutting movement of the cutter 9.

work out of the path of move- ,ne cutter 9 so hat the latter lli n the work when it has its cutting 9 is preferrib. rock-shaft 11 be varied. o s by securing the knife 9 which is a abiy secu of the rec i c a sewing machine, the combinati r thread mechanism, of means to I s mechanism, a cutter for cutting the upperthread, means sustaining said cutter for rotative movement in a fixed horizontai plane,'and means operated by the means for rotating the upper thread mechanism to give the cutter its thread-cutting movement.

2. In a sewing machine, the combination with a frame having a reciprocating needle bar, of means to rotate the needle bar, a cutter forthe upper thread sustained by said frame and mounted for movement in a fixed horizontal direction, and means operated by said rotating means to give the cutter its operative movement.

3. In a sewing machine having upper and under thread mechanism, the combination with work-clamping means, of a cutter for the upper thread movable between the workclamping means and the work in adirection U parallel to the work, and means operated by the upper thread mechanism to actuate the cutter.

4:. In a sewing machine having upper andunder thread mechanism, the combination with work-clamping means, of a swinging upper thread cutting knife operating between the clamping means and the work, and means actuated by the upper thread mechanism to give said knife its thread-cutting movement.

5. In a sewing machine having upper and under thread mechanism, the combination with work-clamping means, of a swinging upper thread cutting knife operating between the clamping means and the work, and means actuated by the upper thread said knife its threadcutting movement at mined stitching operation.

6. In a buttonhole sewing machine, the

combination with a stitch frame carrying the end of a predeterding from the rock-shaft, and means asso ted with the needle-bar rotating s engage said arm thereby to actucutter.

rec-ac g needle bar, a p1 the needie bar, a cutter or the needie-enread operating between the work and the work clamp, and means actuated by said pinion for operating the cutter.

9. in a sewing machine, the combination wlth a Work clamp, of a reciprocating needle, means to rotate the needle, a needle thread cutter operating between the work and the clamp, and means operated by said needle-rotating means to actuate the cutter.

10. In a buttonhole sewing machine, the combination with a bed frame, of a stitch frame carrying upper thread mechanism, means to rotate said upper thread mechanism, a vertically-extending rock-shaft journaled on the stitch frame to turn about a vertical axis fixed relative thereto, an upper thread cutter sustained by the rock shaft, and means operated by the upper thread-rd tating means to turn the rock shaft thereby to actuate the cutter.

11. In a buttonhole sewing machine, the combination with a bed frame, of a stitch frame, upper thread mechanism including a reciprocating needle carried by the stitch frame, needle-rotating means, extending rock shaft carried by the stitch frame and turning about a vertical axis a vertically- 1 carried by the rock shaft, an arm on the rock shaft, and a finger carried by said pinion and adapted to engage said arm thereby to 15. In a sewing machine, the combination with a frame, of a reciprocatlng needle mounted thereon, a pinion for turning the operate the cutter tosever the needle thread, 'needle about its axis, a vertically-extending 40 13. In a sewing machine, the combination with a stitch frame carrying upper thread mechanism including a reciprocating needle bar, of means to turn the needle bar about its axis, a rock-shaft secured to said frame to occupy a fixed position relative thereto and extending parallel to the needle bar, a cutter sustained by the rock-shaft, an arm loosely mounted on the rock shaft, a connection between said arm and rock-shaft by which turning movement of the arm in one direction will turn the rock shaft, said arm being free to turn in the opposite direction without operating the rock shaft, and means associated with the needle-bar-turning means to engage said arm thereby to actuate the cutter.

ll. In a sewing machine, the combination with a frame, of a reciprocating needle mounted thereon, a pinion for rotating said needle, a vertically-extending rock shaft journaled to the frame and occupying a fixed position relative thereto, a needle thread cutter carried by the rock shaft, an arm loose on the rock shaft, a connection between said arm and rock shaft by which movement of the arm in one direction will turn the rock shaft, said arm being free to turn in the opposite direction without turning the rock shaft, and a finger carried by said pinion and adapted to engage the arm as the pinion rotates.

rock shaft journaled to said frame, a needle thread cutter carried by the rock shaft, an arm loosely mounted on the rock shaft, connections between the arm and rock shaftwhereb movement of the arm in one direction wi 1 turn the rock shaft, said arm being free to turn in the opposite direction-without turning the rock shaft, a return spring acting on the rock shaft, a stop to limit the a with upper thread mechanism, of means to a turn said mechanism about its axis, a cutter for cutting the upper thread, means sustain- 7 ing said cutter for movement in a fixed horizontal plane, and means operated by the devices for turning the upper thread mechanism to give the cutter its thread-cutting movement when the upper thread mecha nism is turning in one direction, said means being inoperative to actuate the cutter when the upper thread mechanism is turning in a the opposite direction. v

In testimony whereof, I'have signed my name to this specification, in the presence of two subscribing witnesses.

FRANK ZALESKI, Witnesses:

Tnoms J. CARTY, FREDERICK W. DAVISON. 

